This study aims to evaluate the tissue development through real time ultrasound of lambs before slaughter in feedlot. It has been used thirty non-castrated lambs; being 10 Dorper x undefined breed, 10 Santa Inês x undefined breed and 10 undefined breed. The experimental units were about 120 days of age and 19,31kg weight of in average. The lambs have received a single and complete diet, containing 15,5% of crude protein and 2,58 Mcal/kg of dry matter. It has not been observed significant effect among the genotypes for any analyzed feature in the beginning of the experiment; however, there was influence of the genotype at the 28th days in feedlot, for the body score, rib eye area and muscularity, in which the lambs Dorper x undefined breed were superior to the undefined breed. It has been verified the same effect at the 56 days in feedlot. The undefined breed lambs have presented higher marbling score than the others. There was positive linear correlation between the growing behavior of Longissimus dorsi muscle and adipose tissues with the time in days in feedlot.
Dorper; sheep; ultrasound